Ultrafine magnetic iron oxide nanoparticles (IONPs) coated in oligosaccharides for enhanced contrast in magnetic resonance imaging (MRI).
- Oligosaccharide coating is biocompatible.
- Coating leads to increased water solubility and solution stability.
- Small size promotes a high efficiency contrast enhancement for MRI that can differentiate between tissue and vasculature.
- Improved clearance compared to IONPs coated in larger polymer-coated iron oxide nanoparticles.
Iron oxide nanoparticles (IONPs) are iron oxide particles with a diameter ranging from 1-100 nm. For many years, IONPs have been explored as potential drug delivery and imaging agents as they display unique and desirable properties compared to larger particles. These include enhanced magnetic properties as well as low toxicity, features that make them good contrast agents to enhance MRIs of tissues. As the use of imaging for disease diagnosis and monitoring increases, the market for MRI contrast agents is expected to grow rapidly, however, currently used MRI contrast agents are slowly excreted, raising concerns about potential toxicity. Some additional challenges that have limited the extensive use of IONPs in imaging are their poor water solubility and low stability under physiological conditions.
Emory researchers have developed ultrafine (approx. 3 nm) IONPs coated with oligosaccharides (polymerized glucose) that display both enhanced water solubility and increased solution stability. These IONPs are quickly excreted, reducing potential toxicity concerns, and therefore show promise for potential use in the clinic. Additionally, these coated IONPs have an improved T1/T2 ratio significantly better than the current state-of-the-art gadolinium contrast agents like Multihance™. This contrast enhancement allows for imaging and differentiation of both liver tissue and the surrounding vasculature; imaging both is not possible with either gadolinium contrast agents or existing IONPs.
Oligosaccharide-coated iron oxide nanoparticles have been used for in vivo contrast-enhanced MRI in mice.